In general, a mobile communication system has been advanced to various forms. Such an advanced mobile supporting communication system has supported diverse types of communication as well as simple voice communication. One of representative mobile communication systems is a mobile telephone system and a wireless local area network (W-LAN) system.
Mobile nodes of such mobile communication systems also have been abruptly advanced to receive not only a one-to-one (1:1) communication service but also a one-to-N (1:N) communication service. For example, the one-to-N communication service may be a multimedia service such as a TV service or a movie service.
Meanwhile, a mobile communication system includes not only mobile nodes capable of supporting a Mobile Internet Protocol (MIP) but also mobile nodes incapable of supporting the MIP. In order to support the MIP, a mobile node must complicated structures because it must support high specification. Therefore, it is difficult to implement all mobile nodes to support a MIP function. Accordingly, a method for supporting a MIP in a network was introduced. As an example thereof, a Proxy Mobile IP (PMIP) scheme was introduced.
The PMIP is a protocol for supporting mobility in a network base without implementing a MIP function in a mobile node. Such a PMIP scheme was developed as a communication protocol with only unicast communication. However, as described above, a PMIP based communication system needs to support not only one to one communication but also one to N communication. Here, the one to N communication is referred as multicast communication. Many studies have been in progress to provide various services such as IPTV by supporting multicast communication in an Internet Engineering Task Force (IETF) which standardizes a PMIP technology for supporting a Multicast service.